Question

When a sound wave travels directly toward a hard wall, the incoming and reflected waves can combine to produce a standing wave. There is an antinode right at the wall, just as at the end of a closed tube, so the sound near the wall is loud. You are standing beside a brick wall listening to a 35 Hz tone from a distant loudspeaker. How far from the wall must you move to find the first quiet spot? Assume a sound speed of 340 m/s.

Answer 1

Solution:

for first quiet spot n = 1

=> f = nV/4L   

=> 35  =1 * 340 / 4 * L

=> L = 0.41 m

thanks.